Answer: 1
/2 (
x
2 − 16
x + 6
)
Step-by-step explanation:
The weight in 1980 is
kilograms
<em><u>Solution:</u></em>
From 1980 to 1990, Lior’s weight increased by 25%
His weight is "k" kilograms in 1990
<em><u>To find: weight in 1980</u></em>
This is a percentage increase problem
Let "x" be the weight in kilograms in 1980
<em><u>The percentage increase is given by formula:</u></em>

Here,
Initial value in 1980 = x
Final value in 1990 = k
Percentage increase = 25 %
<em><u>Substituting the values in formula,</u></em>

Thus the weight in kilograms in 1980 is 
Since triangle ABC is isosceles, then angles 1 and 9 are congruent.
4x + 3 = 9x - 47
-5x = -50
x = 10
m<1 = 4x + 3 = 40 + 3 = 43
m<1 = m<9 = 43
Triangle DBE is equilateral, so it is also equiangular.
m< 4 = m<5 = m<6 =60
Angles 3 and 8 are supplementary to congruent angles that measure 60 deg, so 180 - 60 = 120, so
m<3 = m<8 = 120
For angles 2 and 7, use the sum of the measures of the angles of a triangle is 180 deg.
m<1 + m<2 + m<3 = 180
43 + m<2 + 120 = 180
m<2 + 163 = 180
m<2 = 17
m<2 = m<7 = 17